beg the question
Assuming the point you should prove vs. merely raising a question.
To beg the question is to assume the conclusion as if it were already proved: We can trust him because he is honest. The reason only restates the conclusion: to call him honest is to say he can be trusted. A common error is to use beg the question to mean raise a question, as in The empty parking lot begs the question of whether the store is open. Use raise the question instead: The empty parking lot raises the question of whether the store is open.
Examples
UseSaying the rule is fair because it is just begs the question. (the reason restates the claim)
UseThat raises the question of cost. (a question is asked; nothing is assumed)
AvoidThat begs the question of cost. (if you mean only that it raises the question)
Dictionaries now also list beg the question meaning “raise the question.” However, many people still consider this use an error, and they judge the speaker who uses beg the question this way.